This invention relates to a process for the preparation of 3'-halodiphenylethers.
The preparation of certain diphenylethers is generally reported in the literature to be accomplished by reacting a suitably substituted phenol or alkali metal salt thereof with a suitably substituted halobenzene in the presence of an alkaline agent in a polar aprotic solvent and optionally including a catalyst. See, for example, U.S. Pat. Nos. 3,966,453; 3,950,435; 4,046,789; 4,093,446; 4,358,308 and Canadian Pat. No. 1,079,303.
Diphenylethers prepared by the above techniques are also generally reported in the literature to be used as precursors in preparing certain other diphenylether derivatives. For example, the 4'-halo or 4'-nitro derivatives are prepared by halogenating or nitrating an otherwise suitably substituted diphenylether. Further, 3'-hydroxydiphenylethers can be converted to alpha-oxymethylene carboxylic esters by condensation with alpha-halo esters in the presence of bases such as potassium carbonate or hydroxide. These alpha-oxymethylene carboxylic esters can then be converted to the corresponding carboxylic acids, acid chlorides or amides. Still further, 3'-alkoxydiphenylethers can be made by reacting the corresponding 3'-halodiphenylethers prepared by the above described techniques with a carbinol in an inert nonpolar solvent in the presence of base.